In general, in a so-called direct injection type gasoline engine having a cylinder injector, the fuel injection in a latter period of the compression stroke and the largely delayed ignition are made during the fast idling after the beginning of the cold start of engine so that after the fuel component unburnt in the combustion stroke has been exhausted from a combustion chamber, it after-burns in an exhaust port or an exhaust manifold to facilitate the warming-up of catalyst by using the resultant hot exhaust gas and restrict the discharge of HC.
However, a demand still exists for further improving the warming-up of catalyst and more restricting an amount of discharged HC during the cold start. On the other hand, for example, in Japanese Patent Application Laid-open No. 2001-73854, there is a disclosure that in a gasoline engine of a so-called dual-injection type having an air intake passage injector in addition to a cylinder injector, the fuel is separately injected from each of the injectors during the fast idling.
In the conventional fuel injection pattern or style, however, it is impossible to reduce an amount of discharged HC to a sufficiently low level during the cold start. While, when such a separate fuel injection is carried out, the combustion stability; i.e., the torque variation; becomes worse in comparison with the direct injection type, whereby it is necessary to adopt the optimum fuel injection style in the cold start in view of the above point.